Metallic cartridge belt link



P. O. PERSSON METALLIC CARTRIDGE BELT-LINK May 20, 1947.

. Filed Jan. 14, 1942 Patented May 20, 1947 METALLIC CARTRIDGE BELT LINK Per 0. Persson, Chicago, 111., assignor, by mesne assignments, to the United States of America, as represented by the Secretary of War Applicatibn January 14, 1942, Serial No. 426,661

1 Claim.

My invention relates to metallic links for cartridge belts used with rapid fire or machine guns. The invention refers particularly to that type of link such as is disclosed in Laystrom Patent No. 2,232,071, dated February 18, 1941. This type of link comprises a transversely extending body from the ends of which, in one direction, extend spaced apart loops in axial alignment and from the other edge of the body extends a hinge loop, the two spaced apart circular loops receiving respectively the body or firing end and the contracted or bullet end of the cartridge shell, while the circular hinge loop of a link extends between the cartridge receiving loop of the adjacent link to receive the shell body, the shells thus functioning as hinge pins in the assembly of links to form a belt which is fed through a feed passageway in the breach of a gun for successive locationing of cartridges for firing of their bullets through the gun barrel.

The links must be designed to permit adequate hinge clearance and lateral flexibility of the belt so that the belt will travel easily without binding through the gun feed passageway, and furthermore the distance between the axis of the cartridge supporting loops and the axis of the hinge loop of a link must be maintained within certain tolerances against the strain to which a belt is subjected through handling, or during its passage through the gun. After manufacture of the links they are therefore tested in suitable testing devices, as for example in a testing machine such as is disclosed in the pending application of I-Iilding A. Laystrom and Per Persson, Serial No. 388,504, filed April 14, 1941. Such testing of the links involves subjection to a stretch resisting test under application of a predetermined force, and after the test, the distance between the loop axes must be within the predetermined tolerance before the link is fit to be used in a belt.

In the links of the type referred to, the weakest spot has been found to be along the base end of the hinge loop and particularly along its line of juncture with the body, and under test pull, or pull stress in the belt, the hinge loop of a weak link would bend along its base portion and the loop would open up so as to increase the distance between the hinge loop axis and the axis of the cartridge holding loops beyond the allowed tolerance and the defective link would of course interfere with proper feeding of the belt through the gun.

The important object of my invention is therefore to strengthen the hinge loop by outward deflection of the metal of the hinge loop to form an external strengthening rib extending longi-.

tudinally along the base portion of the loop midway between its sides and extending a distance across the link body from which the loop extends. With a certain size of link of the type referred to,

- the standard method of testing has been to subject the link to a pound stretch pull, and where the links are not provided with my improved strengthening rib, the stretch set on some of the links would range approximately three thousandths of an inch to sixteen thousandths of an inch, which range would be beyond the permitted tolerance, but in the same type of links in which the strengthening rib is applied, the stretch set is reduced to a range from approximately zero to three thousandths of an inch, which is well Within the permissible stretch tolerance.

Referring to the drawing,

Figure 1 is a plan view of a number of links forming part of a belt assembly;

Figure 2 is a section on plane IIII of Fig. 1;

Figure 3 is an end view of a link; and

Figure 4 is a section on plane IV-IV of Fig. 3.

The link shown comprises the transversely extending body part Ill from whose ends ill and 12 extend in one direction the loops l3 and i4, and from the middle portion of the body extends the loop 15. The loops l3 and M are circular, and coaxial and separated by the space IS. The loop [5 is circular with its axis parallel to the axis of the loops l3 and M, the loop l5 being opposite the space 16 and of less width than this space. When the links are assembled to form a belt, the loop [3 receives the body or firing end i? of the cartridges and the loop 14 is contracted radially so as to snugly receive the contracted or bullet holding end [8 of the cartridge. The loop l5 of each link extends into the space [6 of the next link so as to receive the cartridge body, the cartridges thus functioning as hinge pins for the links. In addition to the width of the hinge loop being slightly less than the width of the space Hi, the inner diameter of the hinge loop is slightly greater than the outer diameter of the cartridge body so that the belt will have ample lateral flexibility and easy hinge move ment so that the belt may easily travel through the gun breach without binding for locationing of the cartridges for accurate firing of the bullets through the gun barrel. To further ease the hinging movement and add to the lateral flexibility of the belt, the plane of the ends I l and l 2 of the body 10 are offset from the middle portion 3 of the body from which the hinge loop i5 extends so as to leave adequate space 1 between the body of each link and the hinge loop of the next link for entrance of pawls, fingers or teeth forming part of the belt feeding mechanism. The weak-' est part of the link under test pull or under strain when the belt is in use, is the portion X at the base end of the hinge loop and particularly along its line of junction with the body 10. If the loop along this portion X bends beyond the elastic limit, the loop will distort or open so that the distance between the loop axis and the axis of the cartridge loops l3 and 14 will be greater than the permitted tolerance, and the link is therefore defective, and if such opening of the hinge loop occurs during travel of the belt through a gun, the feed accuracy will be interfered with and the gun may jam. In

accordance with my invention, I strengthen the portion X of the hinge loop by outward deflection of the. metal to provide an external strengthenin rib or head I!) extending longitudinally preferably midway between the loop edges and with this rib extending acrbss the line of junction of the loop with the body and part way across the body I 9, the extent of the rib being such that it will not interfere with hinge clearance and flexibility of the belt nor encroach on the feeding space 1/. Furthermore, by restricting the location of the strengthening head to the base portion of the hinge loop, the height of the loop will not be increased sufficiently to interfere with smooth and easy travel of the belt through the feed passageway of the gun.

The provision of the strengthening bead or rib will not materially increase the cost of manufacture of the links as a simple punch operation will form the bead at any suitable part of the die assembly throughwhich the blank is fed from which the link is formed.

I have thus produced a simple but very efiicient means for greatly strengthening links of the type referred to without interfering with the 4 proper functioning of the links in the assembled belt when being fed through a gun.

Having described my invention I claim as follows:

A cartridge belt link formed from an integral sheet of metal and comprising a body, a pair of cartridge-receiving substantially closed loops extending in the same direction from an edge of said body substantially at the ends thereof, said loops being in spaced axial alignment relative to each other forming a gap therebetween and a hinge loop portion extending in a direction opposite to said pair of cartridge-receiving loops and from an edge parallel to said first-mentioned edge of said body at the middle portion thereof, said hinge loop portion and said middle portion forminga substantially closed hinge loop in longitudinal alignment with said gap, the axes oi all said loops being parallel in a common plane, said hingeloop portion having a peripheral part thereof deflected outwardly of the same, said body having a part deflected outwardly thereof and forming an extension of said first deflected part, said deflected parts being in the same plane, said latter plane being normal to said common plane, thereby forming a continuous bead reinforcing said hinge loop against distortion, said hinge loop being substantially closed upon itself at said first-mentioned edge and each of said cartridge-receiving loops being substantially closed upon itself adjacent said first-mentioned edge.

PER O. PERSSON.

REFERENCES CITED The following references are of record in the -file of this patent:

FOREIGN PATENTS 

